1. Field of the Invention
The present invention relates to an apparatus for reading-out the setting of number wheels of a number barrel mechanism with switching pinions on an axle within the circumference of the number wheels. By way of the pinions, the respective lower value number wheel at the end of a complete revolution rotates the higher value number wheel further through one numeral or one scale part.
2. Discussion of the Prior Art
Different kinds of measuring instruments are known in which the measured magnitude is added up and indicated by a mechanical number barrel mechanism. Examples of this are volume-measuring instruments for gas and water or mechanical electricity meters, in which the measured volume or the measured energy is transmitted by a mechanical step-down gear, which is matched to the instrument, to a number barrel mechanism. The number barrel mechanism in that case indicates the quantity measured since the last zero setting or since first being put into commission. For determining the consumption during a certain period, the state of the number barrel mechanism is read off at the beginning and at the end of this period. A common construction for the number barrel mechanism consists of an axle, on which the number wheels are mounted to be rotatable and on the circumference of which the numerals 0 to 9 are applied, as well as of a second axle, which lies externally of the number wheels, with switching pinions rotatable thereon in such a manner that the respective lower value number wheel in the last tenth of a revolution steps the next higher value wheel forward by one tenth of a revolution. In a different construction of the number barrel mechanism the switching pinions are mounted on an axle within the circumference of the number wheels. Such a number barrel mechanism is known, for example from U.S. Pat. No. 4,031,386.
This classic type of number barrel mechanisms is very useful for many purposes and continues to be usable. In case of need, the counter settings must, however, be read off by a person and intermediate totals, for example for statistics and provision of accounts, must be computed.
From U.S. Pat. No. 3,732,404, a solution is known for the electronic reading-out of a number barrel mechanism, in which the continuous rotational movement of the number wheels is translated into a snapping movement. From European reference EP 0 660 263 A1, a solution is known for the electronic reading-out of a number barrel mechanism with switching pinions lying externally of the number wheels, which mechanism comprises five axially arranged one-way light barriers for each number wheel.
The present invention is based on the object of providing a reading-out equipment for a number barrel mechanism with switching pinions mounted on an axle within the number wheels. The equipment, via simple means, yields a high resolution on the scanning of a number wheel setting and operates independently of the drive of the number barrel mechanism and does not influence the drive in any manner.
The reading-out equipment according to the invention is distinguished in that the state of the display of a mechanical number barrel mechanism with inwardly disposed switching pinions is read out contactlessly and load-free by means of radially arranged light barriers.
Several light barriers, which consist of one light source and several receivers or of several light sources and one receiver, are present for each number wheel.
The number wheels comprise light-permeable and light-impermeable code segments, by means of which together with the light barriers, information can be ascertained concerning the setting of the individual number wheels.
The light barriers are arranged radially on a semicircle and, for each number wheel, consist of an internal centrally arranged opti-electronic element and several elements arranged peripherally in a semicircle.
For the purposes of focussing and association of the light beams with the corresponding receiver or with the corresponding receivers, the internal centrally arranged optical element can, for example, be surrounded by a star-shaped multiple prism.
The peripheral elements are formed as glass-like optical conductors and serve as optical signal conductors between the number barrel mechanism and, by way of further opti-electronic elements, the signal inputs of a microprocessor.
During one complete revolution of each number wheel, more than 10 different states are produced in the form of a multiplace digital information. In one exemplary embodiment, 30 states with a five-place digital information are produced.
For the avoidance of undefined intermediate settings during the transition from one reading-out position to a next reading-out position, the Gray code is applied. In the case of the Gray code, only a single bit of a binary information is varied during the transition from one position to the next.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of the disclosure. For a better understanding of the invention, its operating advantages, and specific objects attained by its use, reference should be had to the drawing and descriptive matter in which there are illustrated and described preferred embodiments of the invention.